A number of recent papers have dealt with such properties of clay minerals as their compositions, assemblages, contents and crystallinities,which can reflect the periodic climate changes of the mineral sources and help to reconstruct paleoclimate. Due to the sensitivity of the clay minerals, however, any climatic influence upon the compositions of clay minerals can be easily covered up by extra-climatic events such as source rock,sedimentary environment,and diagenesis. Therefore, both climatic effects and extra-climatic influence should be considered when the clay minerals are used to reconstruct paleoclimate.